Controlled preparation of core–shell polystyrene/polypyrrole nanocomposite particles by a swelling–diffusion–interfacial polymerization method

Polystyrene/polypyrrole (PS/PPy) core–shell nanocomposite particles with uniform and tailored morphology have been successfully synthesized using the “naked” PS particulate substrate with the aid of a proposed strategy, the so-called swelling–diffusion–interfacial polymerization method. After initially forming pyrrole-swollen PS particles, diffusion of the monomer toward the aqueous phase was controlled through the addition of hydrochloric acid, eventually leading to its polymerization on the substrate particle surface. This process allows the nanocomposite particles to possess uniform and intact PPy overlayer and affords much more effective control over the structure and morphology of the resultant nanocomposites by simply changing the PS/pyrrole weight ratio or the addition amount of the doping acid. In particular, the nanocomposite particles with a thin, uniform, and intact PPy overlayer and their corresponding PPy hollow particles were obtained at a low addition amount of pyrrole. The resultant nanocomposite particles have been extensively characterized using scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and thermogravimetry.     

Conductive polypyrrole via enzyme catalysis

Laccase catalyzes the polymerization of pyrrole into a conducting polymer using dioxygen as the terminal oxidant. This finding is significant, because it identifies an enzymatic route, and thus an environmentally benign method, for preparing a technologically important polymer. In addition, the rate of oxidation of pyrrole increases when the redox molecule, ABTS [2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonate)], is included in a reaction medium that contains laccase. This increase in rate occurs because laccase catalyzes the oxidation of ABTS to ABTS*. In addition to laccase, the biocatalytically generated ABTS* oxidizes pyrrole to its corresponding radical cation to yield polypyrrole. Moreover, oxidation of pyrrole by ABTS* regenerates ABTS for subsequent biocatalytic turnover. Including ABTS in the reaction medium has two important consequences for the final product: (a) The reaction proceeds rapidly enough to form polymeric films instead of oligomeric precipitates, and (b) ABTS remains within the polymeric film as a redox-active dopant. The charge transport properties of the resulting polymers, both with and without ABTS as the counteranion, are compared to those of other conducting materials including polypyrrole prepared electrochemically or chemically.     

Synthesis of polypyrrole films for the development of ammonia sensor

In the present investigation, we have synthesized a polypyrrole films by chemical polymerization technique for the development of ammonia sensor. The polypyrrole films were synthesized in an aqueous acidic medium on glass substrate with mild oxidation of ferric chloride at temperature 29°C. The concentrations (molar) of monomer (pyrrole), oxidant (ferric chloride), and dopant (polyvinyl sulfonate) have been optimized for the uniform and porous surface morphology of the synthesized polypyrrole film. The synthesized films were characterized by scanning electron microscopy, ultraviolet‐visible, and Fourier transforms infrared spectroscopy. Ammonia gas sensing behavior of polypyrrole films was studied by using indigenously developed gas sensing chamber. The synthesized polypyrrole film with optimized process parameters shows excellent and reproducible response to low concentration (100 ppm) of ammonia gas. Copyright © 2007 John Wiley & Sons, Ltd.     

Synthesis,core-shell structures and properties of fluorene/polypyrrole composite

In the current study, fluorene/polypyrrole composite with the core-shell structure has been synthesized by in situ oxidative polymerization of pyrrole in the presence of fluorene. Composite was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. Electrical performance of the composite prepared at various reaction conditions was tested. The composite has the best performance of electrical conductivity when FeCl₃–pyrrole molar ratio is equal to 3 and the reaction time is 18 h. It was found that polypyrrole could be formed on the surface of fluorene due to strong π–π interactions between the fluorene core and the polypyrrole shell.     

Electrochemical copolymerization of pyrrole and 2,2-bithiophene and semiconducting characterization of the resulting copolymer films by electrochemical impedance spectroscopy and photoelectrochemistry

The electrochemical copolymerization of pyrrole and bithiophene was studied at a polymerization potential of 1.1 V for various monomer ratios. The cyclic voltammograms showed that the electrochemical properties of the resulting copolymer films changed gradually from those of polypyrrole to polybithiophene with an increase in concentration of bithiophene in the initial electrolyte. The evidence for copolymer formation is based on the analytical results of electrospray ionization mass spectroscopy, thermoanalysis, and Raman spectroscopy. The results showed that cooligomers and homooligomers were found in the electrolyte after copolymerization. The difference between the morphology of a copolymer of pyrrole and bithiophene and a polymer mixture of polypyrrole and polythiophene was demonstrated by scanning electron microscopy. Electrochemical impedance and photocurrent measurements were carried out in order to achieve information on the semiconducting properties of the homopolymers and copolymers obtained. A model of a very thin layer of polypyrrole formed immediately on the electrode surface covered by a thicker copolymer film was developed to explain the results.Dedicated to Zbigniew Galus on the occasion of his 70^th birthday.     

Preparation and characterization of conducting poly(acryloyl chloride)‐g‐ polypyrrole copolymer

The electroactive copolymer of poly(acryloyl chloride) (PAC) and polypyrrole (PPy) can be synthesized by electrochemical polymerization using a polymer precursor which contains a pyrrole moiety in its side chain. Poly(acryloyl pyrrole) (PAP) was synthesized chemically with acryloyl chloride and potassium pyrrole salt and characterized using FT‐IR and ¹H‐NMR spectroscopy. PAP dissolved in dimethyl formamide (DMF), was spin‐coated on a platinum electrode and polymerized electrochemically in the electrolytic mixture solution consisting of acetonitrile, 0.1 M pyrrole, and 0.1 M lithium perchlorate. Constant potential electrolysis showed that pyrrole groups in the precursor were oxidized to form PPy, that is, they acted as grafting centers at which the PPy grew. Scanning electron microscopy (SEM) results and conductivity measurements supported the formation of the graft copolymer. The morphological feature of PAC‐g‐PPy copolymer films showed homogeneous structure, but that of PAC/PPy composite films showed irregular structure. The maximum conductivity of the final products was about 1 S/cm. Copyright © 2002 John Wiley & Sons, Ltd.     

NOVEL POLYPYRROLE MICROSTRUCTURES GENERATED BY DIRECT ELECTROCHEMICAL OXIDATION OF PYRROLE ON p-TYPE SILICON SUBSTRATE

Polypyrrole microstructrues with morphology like bowls, cups, goblets and bottles have been electrochemicallygenerated by direct oxidation of pyrrole on p-silicon substrate in the aqueous solution of camphorsulfonic acid. The well-ordered microstructures can stand upright on the working electrode surface and their morphological features can be easilycontrolled by changing the electrochemical polymerization conditions. The growing process of microstructures was studiedby scanning electron microscopy. The microstryctures made of polypyrrole films in doped state were charaterized by Raman and Infrared spectra.     

多巴胺改性聚吡咯衍生掺氮多孔碳材料的制备及其超电容性能

含氮聚合物材料在惰性气氛下热解能够产生掺氮多孔碳材料. 基于化学聚合法合成多巴胺(DA)改性的聚吡咯(PDA-PPy), 高温热解制备出掺氮多孔碳材料(NPC). 用傅里叶变换红外(FTIR)光谱, 拉曼光谱, X射线光电子能谱(XPS)分析和扫描电镜(SEM)研究其结构与形貌. 随着DA 与吡咯(Py)单体的摩尔比不断变化,PDA-PPy的形貌也随之改变, 进而影响NPC的超电容性能. 循环伏安和恒流充放电测试表明, 当DA与Py 单体的摩尔比为0.5时, 在0.5 A·g^-1的电流密度下, NPC的比电容可以达到210 F·g^-1, 电流密度为10 A·g^-1时, 比电容可以达到134 F·g^-1, 电容保持率为63.8%.     

聚吡咯/氧化石墨烯层状复合材料的制备及其在超级电容器中的应用(英文)

通过将吡咯单体在低温下与氧化石墨烯进行原位聚合,获得聚吡咯/石墨烯(Ppy/CRGO)复合材料.采用场发射电子显微镜(FESEM)、红外(FT-IR)和热重分析(TGA)对复合物的表面形貌、结构进行表征.FESEM结果表明,通过控制氧化石墨烯(GO)和吡咯单体的质量比例,可以对复合物的层状和厚度进行调控.FT-IR和TGA结果表明,聚吡咯(Ppy)是通过化学键合的方式与氧化石墨烯复合在一起.通过机械冷压法将粉末状Ppy/CRGO复合物压成圆片电极,并探讨了石墨烯和聚吡咯复合比例、反应时间、烘干温度和孔隙率等因素对Ppy/CRGO复合物电极的电学和电化学性能的影响.结果表明,Ppy与CRGO质量比为10∶1所制得的Ppy/CRGO复合物的电容量为421 F·g-1,通过在电极中引入孔隙,电容量能进一步提升为509 F·g-1.     

Surface modification of FePO4 particles with conductive layer of polypyrrole

Polypyrrole–FePO₄ powder was synthesized by an oxidative polymerization of pyrrole monomer on the surface of FePO₄ powder. The polymerization reaction was initiated using hydrogen peroxide in an acidified solution and catalysed with Fe³⁺. The samples were investigated by light microscopy (LM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). These methods confirmed the presence of polypyrrole on FePO₄ particles and its homogeneous distribution in the composite material. To determine the PPy content in the PPy–FePO₄ composites a thermogravimetric analysis was used. Cyclic voltammetry curves (CV) were measured and compared in a non-aqueous lithium salt solution for electrodes consisting of pellets made from pure FePO4 and FePO₄/PPy. Electrochemical impedance spectroscopy (EIS) showed that coating of PPy significantly decreases the charge transfer resistance of PPy–FePO₄ electrodes.     

Double template electrosynthesis of ZnO nanodot array

This communication describes the preparation of highly-ordered nanodot arrays of ZnO, a technologically important material, by the double template approach developed by Bartlett and co-workers. Colloidal polystyrene spheres were used as the primary template, and electrodeposited polypyrrole was used as the secondary template in this study. The ZnO nanodot arrays were prepared on a polycrystalline Au substrate by electrodeposition using the pyrrole secondary template after making it insulating by potentiodynamically deactivating it. The ZnO nanodot array was characterized by scanning electron microscopy, energy-dispersive X-ray analyses, and laser Raman spectroscopy.     

A polypyrrole/polymethylene pattern on gold using a micro-contact printing technique

A micro-contact printing technique was used to fabricate a polypyrrole/polymethylene pattern on a gold surface. ω-(N-Pyrroyl)undecanethiol (PyC₁₁SH) acts as ink for the generation of a pyrrole-terminal monolayer patterned on gold. This monolayer-patterned surface functions as a resist for the selective growth of polymethylene by catalytic decomposition of diazomethane on the gold surface. It also functions as a monomer for the electrochemical polymerization of pyrrole on the PyC₁₁SH monolayer-patterned surface. The polypyrrole/polymethylene pattern was fabricated by an electrochemical polymerization method. The polypyrrole was grown on the pyrrole-patterned surface by potential scanning between 0.0 and 1.2 V vs. Ag wire. The thickness of the polypyrrole growth increases with the increasing number of cycles. The structural features of the patterned surface can be determined by scanning electron microscopy and atomic force microscopy. Electronic Publication     

Transition Metal Salt Doping on Polypyrrole/MWCNT Composites for Supercapacitor Applications

Polypyrrole doped by Zn²⁺ ions was synthesized as nanocomposites with MWCNT by in-situ oxidative polymerization and investigated as electrode material for supercapacitors. The uniform coating of polypyrrole on MWCNT was characterized by field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM). The effect of Zn²⁺ ions were characterized by Fourier transform infrared (FTIR) spectroscopy. The electrochemical performances were investigated by cyclic voltammetry (CV), constant current charging/discharging cyclic test (CC) and electrochemical impedance spectroscopy (EIS) using a three-electrode system. The doped polypyrrole composites show higher specific capacitance and better cyclic stability.     

Synthesis,characterization and X‐ray shielding properties of polypyrrole/lead nanocomposites

Novel radiation shielding nanocomposites based on a conducting polymer were fabricated and investigated to determine their abilities in attenuation of X‐rays. Polypyrrole/Pb nanocomposites were prepared through chemical reduction of lead salt by a facile solution‐phase method using t‐BuOLi‐activated LiH and in situ chemical polymerization of pyrrole in the presence of dodecyl benzene sulfonic acid as dopant and surfactant and iron chloride as the oxidant. The morphology, composition, and electrical conductivity of resulting products were characterized by scanning electron microscopy, transmission electron microscopy, X‐ray diffraction analysis, energy‐dispersive X‐ray spectroscopy, fourier transform infrared spectroscopy, and standard four‐wire technique, respectively. In order to evaluate capability of nanocomposites in radiation shielding, X‐ray photon interaction parameters such as linear attenuation coefficient, attenuation percentage, and half‐value thickness were determined for the samples with different Pb loadings and thicknesses, at photon energies of 13.95, 17.74, 20.08, 26.34, and 59.50 keV. The investigation was carried out to explore the potential of polypyrrole/Pb nanocomposites as thin and light‐weight radiation shielding materials. Copyright © 2015 John Wiley & Sons, Ltd.     

Conducting graft copolymers of poly(3‐methylthienyl methacrylate) with pyrrole and thiophene

A thiophene‐functionalized methacrylate monomer (3‐methylthienyl methacrylate) was synthesized via the esterification of 3‐thiophene methanol with methacryloyl chloride. The methacrylate monomer was polymerized by free‐radical polymerization in the presence of azobisisobutyronitrile as the initiator. Graft copolymers of poly(3‐methylthienyl methacrylate) (PMTM2) and polypyrrole and of PMTM2 and polythiophene were synthesized by constant‐potential electrolyses. p‐Toluene sulfonic acid, sodium dodecyl sulfate, and tetrabutylammonium tetrafluoroborate were used as the supporting electrolytes. PMTM2‐coated platinum electrodes were used as anodes in the polymerization of pyrrole and thiophene. Moreover, the oxidative polymerization of poly(3‐methylthienyl methacrylate) (PMTM1) was studied with FeCl₃ as the oxidant. The self‐polymerization of PMTM1 was also investigated by galvanostatic electrolysis both in dichloromethane and in propylene carbonate. The structures of PMTM1 and PMTM2 were investigated by several spectroscopic and thermal methods. The grafting process was elucidated with conductivity measurements, Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and scanning electron microscopy studies. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4131–4140, 2002     

Facile synthesis of poly[1‐p (tolylsulfonyl) pyrrole] via Ce (IV)‐pyrrole redox initiating system and polyacrylonitrile blended nanofibers

Chemical polymerization of monomers of electroactive polymers and their processability have some challenges. Chemical polymerization of 1‐p‐(tolylsulfonyl) pyrrole has been realized first time by using Ce (IV)‐pyrrole redox initiating system to obtain poly (1‐p‐[tolylsulfonyl)pyrrole]. Moreover, the achieved polymer was used as a precursor for electrospinning, and their solutions with DMF were used to fabricate nano and submicron fibers via electrospinning method. Polymerization conditions were followed with UV–visible spectroscopy. Surface morphologies were examined with scanning electron microscopy, and elemental analysis measurements were obtained via scanning electron microscopy/energy‐dispersive X‐ray. Attenuated total reflection spectroscopy was used to record the characteristic peaks of the nanofiber webs before and after polymerization. Surface morphology of the polymer domains was examined with atomic force microscopy. Inherently conductive polymer, poly (1‐p‐[tolylsulfonyl)pyrrole] was successfully combined with the PAN and were fabricated to obtain nanofiber webs.     

Synthesize,Characterization, and Corrosion Inhibition of Polypyrrole Thin Films on Copper

Polypyrrole (PPy) coatings were synthesized on copper by electrochemical polymerization of pyrrole monomer in aqueous acidic and basic solutions by cyclic voltammetry. The coatings were characterized with CV, UV-visible absorption spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, and scanning electron microscopy (SEM) techniques. The corrosion protection aspects of PPy coatings have been investigated using the potentiodynamic polarization technique and electrochemical impedance spectroscopy (EIS). The potentiodynamic polarization measurements show that the PPy coating has ability to protect the copper against corrosion. It was concluded that a complete corrosion protective PPy film could not be obtained through direct electro-oxidation procedure. This may be due to copper dissolution in the monomer oxidation potential range.     

基于静电吸附作用制备PPy/CNTs复合材料

通过添加十二烷基苯磺酸钠(SDBS), 在碳纳米管(CNTs)表面引入具有静电吸附作用的基团, 使吡咯单体附着于CNTs表面, 然后发生化学原位聚合, 得到了由片状聚吡咯(PPy)包覆CNTs所构成的PPy/CNTs复合材料, 开辟了一条易于工业化生产制备PPy/CNTs复合材料的途径. 所得材料和CNTs借助傅立叶变换红外光谱、扫描电子显微镜、透射电子显微镜等设备进行了成分和形貌的表征; 并将所得材料组装成电化学超级电容器, 进行了电化学性能测试. 研究结果表明, 加入SDBS后, 吡咯单体能很好地吸附于CNTs表面; CNTs的应用细化了PPy的颗粒, 改善了PPy的导电性能和机械性能, 使PPy/CNTs复合材料呈现出多孔状; 其电化学容量达到101.1 F·g-1(有机电解液), 是同样制备条件下所得纯PPy电化学容量(19.0 F·g-1)的5倍多, 约是所用纯CNTs电化学容量(25.0 F·g-1)的4倍.     

Electrochemical synthesis and characterization of poly(pyrrole-co-tetrahydrofuran) conducting copolymer

The direct electrochemical copolymerization of pyrrole and tetrahydrofuran in various monomer ratios was carried out by potentiostatic methods in nitromethane solution. The copolymer has been characterized using FT-IR, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermal gravimetrical analysis (TGA), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and elemental analysis. The results showed that the electrochemical oxidation of pyrrole and tetrahydrofuran comonomers generated true copolymers rather than blends of the two homopolymers. The copolymer showed a better flexibility than pure polypyrrole. The electrical conductivity of the copolymers increases with the amount of polypyrrole in the copolymer between the value of 1.69 S/cm and 0.71 S/cm.     

Principles and applications of electrochemical and optical biosensors

The principles of biocatalytic and bioaffinity biosensors are reviewed with emphasis on electron transfer-type enzyme sensors, optical enzyme sensors and optical immunosensors for homogeneous immunoassay. An enzyme sensor for ethanol was fabricated by electrochemical polymerization of pyrrole onto the surface of platinized platinum-adsorbed alcohol dehydrogenase—NAD—Meldola Blue. Ethanol was determined amperometrically by measuring the oxidative current through polypyrrole. An optical enzyme sensor is exemplified by an acethylcholine sensor based on an optical pH fibre sensor using a thin polyaniline film. The optical immunosensor for homogeneous immunoassay consists of an optical fibre, the end of the which is coated with an optically transparent platinum electrode. With using luminol as a label, highly sensitive homogeneous immunoassay is carried out by measuring the electrochemical luminescence of the label.